SAS 4 Flashcards
a process of drug movement across a cell
Transcellular absorption
a drug movement that go through gaps or tight junctions between cells
Paracellular drug diffusion
what are the two cell membrane theory?
unit membrane theory and fluid-mosaic model
Explains the transcellular diffusion of polar molecules
Fluid mosaic model
what is the major absorption process of most drugs?
passive diffusion
this law denotes that drug molecules diffuse from a region of high drug concentration to a region of low drug concentration
Flick’s law of diffusion
represents the lipid water
partitioning of a drug across the hypothetical membrane in
the mucosa
Partition coefficient
defined as the amount of a drug that diffuses
across a membrane of a given unit area per unit
time
Diffusion coefficient
Ability to transport drug against a concentration
gradient from regions of low drug
concentration to regions of high drug
concentrations
Active transport
- Saturable and highly selective for the drug
- Carrier-nmediated transport system
Facilitated diffusion
are present throughout the body and are involved in
transport of a diverse group of hydrophobic drugs, natural products, and peptides
Efflux pumps
endocytosis and exoxytosis belongs to what transport system?
Vesicular transport
- Very small molecules (such as
urea, water, and sugars) are
able to cross cell membranes
rapidly, as if the membrane contained channels or pores - Small molecules including drugs move through the channel by
diffusion more rapidly than at
other parts of the membrane.
Pore transport
Drugs that ionise at all ph conditions absorbed after complexing with oppositely charged ions
Ion-pair transport
Structure-specific drugs with affinity for carriers transported from specific sites
Carrier-mediated transport
